Nazanin is married to husband Richard and the pair have daughter Gabriella together

A quid pro quo ‘ransom’ agreement has never been formally proposed by Iranian officials.

But British ministers have been left in little doubt that is the price for Nazanin’s freedom, as the long-standing demands always resurface whenever secret talks over her jailing in April 2016 take place.

The bungling Foreign Secretary’s mistaken declaration that she was in Iran to train journalists rather than there on holiday was seized on by hardliners as a reason to double her jail term to 10 years.

It also comes as Boris today meets Nazanin’s husband Richard Ratcliffe today for the first time.

The pair will discuss with Mr Ratcliffe plea for the government to grant “diplomatic protection” to his wife as a way to try to force Iran to release her.

Top of the list of Iran officials’ demands is the £400m to settle the long-running Chieftan tanks row.